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https://github.com/c64scene-ar/llvm-6502.git
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In the commit message to r185476 I wrote: >The PowerPC-specific modifiers VK_PPC_TLSGD and VK_PPC_TLSLD >correspond exactly to the generic modifiers VK_TLSGD and VK_TLSLD. >This causes some confusion with the asm parser, since VK_PPC_TLSGD >is output as @tlsgd, which is then read back in as VK_TLSGD. > >To avoid this confusion, this patch removes the PowerPC-specific >modifiers and uses the generic modifiers throughout. (The only >drawback is that the generic modifiers are printed in upper case >while the usual convention on PowerPC is to use lower-case modifiers. >But this is just a cosmetic issue.) This was unfortunately incorrect, there is is fact another, serious drawback to using the default VK_TLSLD/VK_TLSGD variant kinds: using these causes ELFObjectWriter::RelocNeedsGOT to return true, which in turn causes the ELFObjectWriter to emit an undefined reference to _GLOBAL_OFFSET_TABLE_. This is a problem on powerpc64, because it uses the TOC instead of the GOT, and the linker does not provide _GLOBAL_OFFSET_TABLE_, so the symbol remains undefined. This means shared libraries using TLS built with the integrated assembler are currently broken. While the whole RelocNeedsGOT / _GLOBAL_OFFSET_TABLE_ situation probably ought to be properly fixed at some point, for now I'm simply reverting the r185476 commit. Now this in turn exposes the breakage of handling @tlsgd/@tlsld in the asm parser that this check-in was originally intended to fix. To avoid this regression, I'm also adding a different fix for this problem: while common code now parses @tlsgd as VK_TLSGD, a special hack in the asm parser translates this code to the platform-specific VK_PPC_TLSGD that the back-end now expects. While this is not really pretty, it's self-contained and shouldn't hurt anything else for now. One the underlying problem is fixed, this hack can be reverted again. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185945 91177308-0d34-0410-b5e6-96231b3b80d8
420 lines
14 KiB
C++
420 lines
14 KiB
C++
//===-- PPCELFObjectWriter.cpp - PPC ELF Writer ---------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#include "MCTargetDesc/PPCMCTargetDesc.h"
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#include "MCTargetDesc/PPCFixupKinds.h"
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#include "llvm/ADT/STLExtras.h"
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#include "llvm/MC/MCELFObjectWriter.h"
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#include "llvm/MC/MCExpr.h"
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#include "llvm/MC/MCValue.h"
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#include "llvm/Support/ErrorHandling.h"
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using namespace llvm;
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namespace {
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class PPCELFObjectWriter : public MCELFObjectTargetWriter {
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public:
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PPCELFObjectWriter(bool Is64Bit, uint8_t OSABI);
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virtual ~PPCELFObjectWriter();
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protected:
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virtual unsigned getRelocTypeInner(const MCValue &Target,
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const MCFixup &Fixup,
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bool IsPCRel) const;
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virtual unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
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bool IsPCRel, bool IsRelocWithSymbol,
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int64_t Addend) const;
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virtual const MCSymbol *ExplicitRelSym(const MCAssembler &Asm,
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const MCValue &Target,
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const MCFragment &F,
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const MCFixup &Fixup,
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bool IsPCRel) const;
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virtual const MCSymbol *undefinedExplicitRelSym(const MCValue &Target,
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const MCFixup &Fixup,
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bool IsPCRel) const;
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};
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}
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PPCELFObjectWriter::PPCELFObjectWriter(bool Is64Bit, uint8_t OSABI)
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: MCELFObjectTargetWriter(Is64Bit, OSABI,
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Is64Bit ? ELF::EM_PPC64 : ELF::EM_PPC,
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/*HasRelocationAddend*/ true) {}
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PPCELFObjectWriter::~PPCELFObjectWriter() {
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}
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unsigned PPCELFObjectWriter::getRelocTypeInner(const MCValue &Target,
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const MCFixup &Fixup,
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bool IsPCRel) const
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{
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MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
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MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
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// determine the type of the relocation
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unsigned Type;
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if (IsPCRel) {
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switch ((unsigned)Fixup.getKind()) {
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default:
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llvm_unreachable("Unimplemented");
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case PPC::fixup_ppc_br24:
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case PPC::fixup_ppc_br24abs:
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Type = ELF::R_PPC_REL24;
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break;
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case PPC::fixup_ppc_brcond14:
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case PPC::fixup_ppc_brcond14abs:
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Type = ELF::R_PPC_REL14;
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break;
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case PPC::fixup_ppc_half16:
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switch (Modifier) {
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default: llvm_unreachable("Unsupported Modifier");
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case MCSymbolRefExpr::VK_None:
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Type = ELF::R_PPC_REL16;
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break;
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case MCSymbolRefExpr::VK_PPC_LO:
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Type = ELF::R_PPC_REL16_LO;
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break;
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case MCSymbolRefExpr::VK_PPC_HI:
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Type = ELF::R_PPC_REL16_HI;
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break;
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case MCSymbolRefExpr::VK_PPC_HA:
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Type = ELF::R_PPC_REL16_HA;
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break;
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}
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break;
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case FK_Data_4:
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case FK_PCRel_4:
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Type = ELF::R_PPC_REL32;
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break;
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case FK_Data_8:
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case FK_PCRel_8:
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Type = ELF::R_PPC64_REL64;
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break;
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}
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} else {
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switch ((unsigned)Fixup.getKind()) {
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default: llvm_unreachable("invalid fixup kind!");
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case PPC::fixup_ppc_br24abs:
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Type = ELF::R_PPC_ADDR24;
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break;
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case PPC::fixup_ppc_brcond14abs:
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Type = ELF::R_PPC_ADDR14; // XXX: or BRNTAKEN?_
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break;
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case PPC::fixup_ppc_half16:
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switch (Modifier) {
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default: llvm_unreachable("Unsupported Modifier");
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case MCSymbolRefExpr::VK_None:
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Type = ELF::R_PPC_ADDR16;
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break;
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case MCSymbolRefExpr::VK_PPC_LO:
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Type = ELF::R_PPC_ADDR16_LO;
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break;
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case MCSymbolRefExpr::VK_PPC_HI:
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Type = ELF::R_PPC_ADDR16_HI;
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break;
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case MCSymbolRefExpr::VK_PPC_HA:
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Type = ELF::R_PPC_ADDR16_HA;
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break;
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case MCSymbolRefExpr::VK_PPC_HIGHER:
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Type = ELF::R_PPC64_ADDR16_HIGHER;
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break;
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case MCSymbolRefExpr::VK_PPC_HIGHERA:
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Type = ELF::R_PPC64_ADDR16_HIGHERA;
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break;
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case MCSymbolRefExpr::VK_PPC_HIGHEST:
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Type = ELF::R_PPC64_ADDR16_HIGHEST;
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break;
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case MCSymbolRefExpr::VK_PPC_HIGHESTA:
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Type = ELF::R_PPC64_ADDR16_HIGHESTA;
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break;
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case MCSymbolRefExpr::VK_GOT:
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Type = ELF::R_PPC_GOT16;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_LO:
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Type = ELF::R_PPC_GOT16_LO;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_HI:
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Type = ELF::R_PPC_GOT16_HI;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_HA:
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Type = ELF::R_PPC_GOT16_HA;
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break;
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case MCSymbolRefExpr::VK_PPC_TOC:
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Type = ELF::R_PPC64_TOC16;
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break;
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case MCSymbolRefExpr::VK_PPC_TOC_LO:
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Type = ELF::R_PPC64_TOC16_LO;
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break;
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case MCSymbolRefExpr::VK_PPC_TOC_HI:
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Type = ELF::R_PPC64_TOC16_HI;
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break;
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case MCSymbolRefExpr::VK_PPC_TOC_HA:
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Type = ELF::R_PPC64_TOC16_HA;
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break;
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case MCSymbolRefExpr::VK_PPC_TPREL:
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Type = ELF::R_PPC_TPREL16;
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break;
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case MCSymbolRefExpr::VK_PPC_TPREL_LO:
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Type = ELF::R_PPC_TPREL16_LO;
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break;
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case MCSymbolRefExpr::VK_PPC_TPREL_HI:
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Type = ELF::R_PPC_TPREL16_HI;
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break;
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case MCSymbolRefExpr::VK_PPC_TPREL_HA:
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Type = ELF::R_PPC_TPREL16_HA;
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break;
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case MCSymbolRefExpr::VK_PPC_TPREL_HIGHER:
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Type = ELF::R_PPC64_TPREL16_HIGHER;
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break;
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case MCSymbolRefExpr::VK_PPC_TPREL_HIGHERA:
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Type = ELF::R_PPC64_TPREL16_HIGHERA;
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break;
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case MCSymbolRefExpr::VK_PPC_TPREL_HIGHEST:
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Type = ELF::R_PPC64_TPREL16_HIGHEST;
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break;
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case MCSymbolRefExpr::VK_PPC_TPREL_HIGHESTA:
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Type = ELF::R_PPC64_TPREL16_HIGHESTA;
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break;
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case MCSymbolRefExpr::VK_PPC_DTPREL:
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Type = ELF::R_PPC64_DTPREL16;
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break;
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case MCSymbolRefExpr::VK_PPC_DTPREL_LO:
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Type = ELF::R_PPC64_DTPREL16_LO;
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break;
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case MCSymbolRefExpr::VK_PPC_DTPREL_HI:
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Type = ELF::R_PPC64_DTPREL16_HI;
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break;
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case MCSymbolRefExpr::VK_PPC_DTPREL_HA:
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Type = ELF::R_PPC64_DTPREL16_HA;
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break;
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case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHER:
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Type = ELF::R_PPC64_DTPREL16_HIGHER;
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break;
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case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHERA:
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Type = ELF::R_PPC64_DTPREL16_HIGHERA;
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break;
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case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHEST:
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Type = ELF::R_PPC64_DTPREL16_HIGHEST;
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break;
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case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHESTA:
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Type = ELF::R_PPC64_DTPREL16_HIGHESTA;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_TLSGD:
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Type = ELF::R_PPC64_GOT_TLSGD16;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_LO:
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Type = ELF::R_PPC64_GOT_TLSGD16_LO;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_HI:
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Type = ELF::R_PPC64_GOT_TLSGD16_HI;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_HA:
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Type = ELF::R_PPC64_GOT_TLSGD16_HA;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_TLSLD:
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Type = ELF::R_PPC64_GOT_TLSLD16;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_LO:
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Type = ELF::R_PPC64_GOT_TLSLD16_LO;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_HI:
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Type = ELF::R_PPC64_GOT_TLSLD16_HI;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_HA:
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Type = ELF::R_PPC64_GOT_TLSLD16_HA;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_TPREL:
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/* We don't have R_PPC64_GOT_TPREL16, but since GOT offsets
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are always 4-aligned, we can use R_PPC64_GOT_TPREL16_DS. */
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Type = ELF::R_PPC64_GOT_TPREL16_DS;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_TPREL_LO:
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/* We don't have R_PPC64_GOT_TPREL16_LO, but since GOT offsets
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are always 4-aligned, we can use R_PPC64_GOT_TPREL16_LO_DS. */
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Type = ELF::R_PPC64_GOT_TPREL16_LO_DS;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_TPREL_HI:
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Type = ELF::R_PPC64_GOT_TPREL16_HI;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_DTPREL:
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/* We don't have R_PPC64_GOT_DTPREL16, but since GOT offsets
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are always 4-aligned, we can use R_PPC64_GOT_DTPREL16_DS. */
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Type = ELF::R_PPC64_GOT_DTPREL16_DS;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_LO:
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/* We don't have R_PPC64_GOT_DTPREL16_LO, but since GOT offsets
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are always 4-aligned, we can use R_PPC64_GOT_DTPREL16_LO_DS. */
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Type = ELF::R_PPC64_GOT_DTPREL16_LO_DS;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_TPREL_HA:
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Type = ELF::R_PPC64_GOT_TPREL16_HA;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_HI:
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Type = ELF::R_PPC64_GOT_DTPREL16_HI;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_HA:
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Type = ELF::R_PPC64_GOT_DTPREL16_HA;
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break;
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}
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break;
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case PPC::fixup_ppc_half16ds:
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switch (Modifier) {
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default: llvm_unreachable("Unsupported Modifier");
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case MCSymbolRefExpr::VK_None:
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Type = ELF::R_PPC64_ADDR16_DS;
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break;
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case MCSymbolRefExpr::VK_PPC_LO:
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Type = ELF::R_PPC64_ADDR16_LO_DS;
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break;
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case MCSymbolRefExpr::VK_GOT:
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Type = ELF::R_PPC64_GOT16_DS;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_LO:
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Type = ELF::R_PPC64_GOT16_LO_DS;
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break;
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case MCSymbolRefExpr::VK_PPC_TOC:
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Type = ELF::R_PPC64_TOC16_DS;
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break;
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case MCSymbolRefExpr::VK_PPC_TOC_LO:
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Type = ELF::R_PPC64_TOC16_LO_DS;
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break;
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case MCSymbolRefExpr::VK_PPC_TPREL:
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Type = ELF::R_PPC64_TPREL16_DS;
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break;
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case MCSymbolRefExpr::VK_PPC_TPREL_LO:
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Type = ELF::R_PPC64_TPREL16_LO_DS;
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break;
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case MCSymbolRefExpr::VK_PPC_DTPREL:
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Type = ELF::R_PPC64_DTPREL16_DS;
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break;
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case MCSymbolRefExpr::VK_PPC_DTPREL_LO:
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Type = ELF::R_PPC64_DTPREL16_LO_DS;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_TPREL:
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Type = ELF::R_PPC64_GOT_TPREL16_DS;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_TPREL_LO:
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Type = ELF::R_PPC64_GOT_TPREL16_LO_DS;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_DTPREL:
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Type = ELF::R_PPC64_GOT_DTPREL16_DS;
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break;
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case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_LO:
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Type = ELF::R_PPC64_GOT_DTPREL16_LO_DS;
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break;
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}
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break;
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case PPC::fixup_ppc_nofixup:
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switch (Modifier) {
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default: llvm_unreachable("Unsupported Modifier");
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case MCSymbolRefExpr::VK_PPC_TLSGD:
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Type = ELF::R_PPC64_TLSGD;
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break;
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case MCSymbolRefExpr::VK_PPC_TLSLD:
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Type = ELF::R_PPC64_TLSLD;
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break;
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case MCSymbolRefExpr::VK_PPC_TLS:
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Type = ELF::R_PPC64_TLS;
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break;
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}
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break;
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case FK_Data_8:
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switch (Modifier) {
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default: llvm_unreachable("Unsupported Modifier");
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case MCSymbolRefExpr::VK_PPC_TOCBASE:
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Type = ELF::R_PPC64_TOC;
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break;
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case MCSymbolRefExpr::VK_None:
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Type = ELF::R_PPC64_ADDR64;
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break;
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case MCSymbolRefExpr::VK_PPC_DTPMOD:
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Type = ELF::R_PPC64_DTPMOD64;
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break;
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case MCSymbolRefExpr::VK_PPC_TPREL:
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Type = ELF::R_PPC64_TPREL64;
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break;
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case MCSymbolRefExpr::VK_PPC_DTPREL:
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Type = ELF::R_PPC64_DTPREL64;
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break;
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}
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break;
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case FK_Data_4:
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Type = ELF::R_PPC_ADDR32;
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break;
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case FK_Data_2:
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Type = ELF::R_PPC_ADDR16;
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break;
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}
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}
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return Type;
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}
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unsigned PPCELFObjectWriter::GetRelocType(const MCValue &Target,
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const MCFixup &Fixup,
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bool IsPCRel,
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bool IsRelocWithSymbol,
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int64_t Addend) const {
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return getRelocTypeInner(Target, Fixup, IsPCRel);
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}
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const MCSymbol *PPCELFObjectWriter::ExplicitRelSym(const MCAssembler &Asm,
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const MCValue &Target,
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const MCFragment &F,
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const MCFixup &Fixup,
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bool IsPCRel) const {
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assert(Target.getSymA() && "SymA cannot be 0");
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MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
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MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
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bool EmitThisSym;
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switch (Modifier) {
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// GOT references always need a relocation, even if the
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// target symbol is local.
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case MCSymbolRefExpr::VK_GOT:
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case MCSymbolRefExpr::VK_PPC_GOT_LO:
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case MCSymbolRefExpr::VK_PPC_GOT_HI:
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case MCSymbolRefExpr::VK_PPC_GOT_HA:
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EmitThisSym = true;
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break;
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default:
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EmitThisSym = false;
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break;
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}
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if (EmitThisSym)
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return &Target.getSymA()->getSymbol().AliasedSymbol();
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return NULL;
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}
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const MCSymbol *PPCELFObjectWriter::undefinedExplicitRelSym(const MCValue &Target,
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const MCFixup &Fixup,
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bool IsPCRel) const {
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assert(Target.getSymA() && "SymA cannot be 0");
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const MCSymbol &Symbol = Target.getSymA()->getSymbol().AliasedSymbol();
|
|
|
|
unsigned RelocType = getRelocTypeInner(Target, Fixup, IsPCRel);
|
|
|
|
// The .odp creation emits a relocation against the symbol ".TOC." which
|
|
// create a R_PPC64_TOC relocation. However the relocation symbol name
|
|
// in final object creation should be NULL, since the symbol does not
|
|
// really exist, it is just the reference to TOC base for the current
|
|
// object file.
|
|
bool EmitThisSym = RelocType != ELF::R_PPC64_TOC;
|
|
|
|
if (EmitThisSym && !Symbol.isTemporary())
|
|
return &Symbol;
|
|
return NULL;
|
|
}
|
|
|
|
MCObjectWriter *llvm::createPPCELFObjectWriter(raw_ostream &OS,
|
|
bool Is64Bit,
|
|
uint8_t OSABI) {
|
|
MCELFObjectTargetWriter *MOTW = new PPCELFObjectWriter(Is64Bit, OSABI);
|
|
return createELFObjectWriter(MOTW, OS, /*IsLittleEndian=*/false);
|
|
}
|